idle surge

[Wheelspin]

this is on the 90. so the idle surges between 700-1200 rpm. sometimes it will die. it seems that the car is running rich from the smell. also there's lots of blue smoke when its cold and you rev the engine. its not oil. takes forever for it to warm up to, probably the thermostat is bad but i dont think that would cause the surging issue. maybe im wrong? i've replaced the temp sensor for the compy (the one with the plastic plug not the stud) and the iac with no change. my theory was the temp sensor was bad tell the compy to rich up the fuel. after no change i tried the iac. still no luck. any ideas guys? :thankyou:

 

[bigblock]

oops lol ^ that was me btw guys not wheelspin. i used my bros compy and forgot to log out

 

[sperold]

Throttle position sensor may be the issue.
If you get the codes, it will tell you what the problem is.
Check on here for a way to get the codes with a paper clip and a lot of threads have the codes listed.

 

[bigblock]

i have a snap on scanner. no codes. ill try the tps. got a spare one

 

[riden2low]

http://www.shophoenixproject.com/ a good site to go to for codes

 

[bigblock]

i tried the tps and saw no change. im starting to think it might be o2 sensors. any thoughts? anyone have any ideas what might cause this? i'll put the scanner on the car and see if any codes come up. try a koer and koeo tests

 

[jayro]

You could try cleaning or replacing the IAB. You should also try the idle reset procedure. If it isnt heating up it will run rich. The ECU runs in a different mode prior to the coolant coming up to temp (cant remember if its called closed or open loop). As far as the blue smoke, blue usually means oil somehow. Since you said its not oil then I dont know.

 

[itwonder]

You need to fix the issue with warm up first so that the engine gets to normal operating temperature. Replace thermostat. Then reset idle.

 

[bigblock]

the thing is the warming up issue has been like that for a year or more. the idle issue started a couple months ago. i'll change the thermostat today just to eliminate that. probably should have done that awhile ago. water pump is new and rad is new so that will complete the set.

 

[rubydist]

the idle issue is almost certainly a bad iac. cleaning them is usually unsuccessful.

the open thermostat will eventually ruin the cats, so fixing that should be a priority, and since it costs less than $10 there is no reason to delay.

 

[bigblock]

i replaced the iac with a BRAND NEW unit. no effect. i replaced the tstat yesterday and the car runs better (duh) but its still surging. i tried resetting the compy ot relearn idle and that didnt work. i'll try to get the car down to my buddies shop to put the scanner on it and run some diagnostics.

 

[mgreen1872]

so I just spent weeks chasing the same problem. IAC did not fix it... turns out I have a vacuum leak around the injector seat seal... replaced the entire set and new intake gaskets now she purrs like a kitten...

 

[bigblock]

wow. ill try sparying carb cleaner to find a leak. thanks for the tip